While embodiments of the present invention may be used for a variety of purposes where it is desired to atomize a liquid by means of a gas, for purposes of disclosure the present invention is herein described as relating primarily to spray nozzles for making snow in flake form for use in covering ski areas and the like for winter sports when natural snowfall has been scanty because of variations in accumulations over a sports season or when it is desired to supplement natural snowfall to make existing surfaces better for sports enthusiasts. The growth of interest in winter sports over the past twenty five years and the increase in the number of participants during that time have, on the one hand, created a considerable business in such sports activity and, on the other hand, created an increased demand for apparatus for artificially making snow to counteract light snowfall and its adverse sports and economic effects.
There has been considerable development in the art since the issuance of what may be called the basic Pierce U.S. Pat. No. 2,676,471 on Apr. 27, 1954 (application filed Dec. 14, 1950) and as well summarized in the Burns U.S. Pat. No. 3,908,903, issued Sept. 30, 1975, the Pierce nozzle (like the nozzle of the present invention) utilizes compressed air mixed with pressurized water for the two purposes of atomizing the water into small droplets and to produce small ice crystals which act as "seeds" to crystallize the droplets into snow, the droplets having been cooled by exposure to the sub-freezing ambient air. The Burns patent lists some thirteen U.S. patents all directed to making snow in various ways, and other patents issuing before and after Burns include Ratnik, U.S. Pat. Nos. 3,829,013, Aug. 13, 1974; Tropeano, 3,831,844, Aug. 27, 1974; White, 3,923,247, Dec. 2, 1975; and Hanson, 4,004,732, Jan. 25, 1977.
A constant problem facing all snow making has been the large quantity of compressed air required to produce a desired quantity of snow, and a further problem has been the noise factor which attends the use of such air. It is therefore the principal object of the present invention to produce snow-making nozzle structure for atomizing water by the use of compressed air in the operation of which the ratio of air to water is low and as a result of which the noise produced in operation of the nozzle is reduced by almost two thirds over conventional nozzles. Actual tests of nozzles embodying the present invention in operation in an ambient temperature of 28.degree. F have shown a 5-to-1 air to water ratio, which is much lower than the prior art has produced at such ambiance under the same conditions.
But embodiments of the present invention may also be used under ambient temperature conditions which are not below or near the freezing point of water but higher to any extent, and a few examples of such uses are: (a) spray drying in the production of soap powder with air being the atomizing agent; (b) cooling gases, as in the manufacture of cement, where the water droplets used for cooling must be in such fine atomization as to evaporate and not contact the cement; and (c) combustion of fuel oils with either air or steam being used to atomize the fuel.
It is therefore a further object of the present invention to produce improved nozzle structure which creates a fine atomization of liquid by means of a pressurized gas for a variety of purposes where the ambient temperatures are at any points above that of water freezing.
To the accomplishment of the above-mentioned objects the various features of the present invention reside in certain constructions, combinations, and arrangements of parts all fully described in the following detailed description of two embodiments and are then set forth in the appended claims by the intentional use of generic terms and expressions that are inclusive in meaning of various modifications.